feat(gemini-web): Add conversation affinity selector

internal/provider/gemini-web/conversation/sanitize.go

@@ -0,0 +1,39 @@
+package conversation
+
+import (
+	"regexp"
+	"strings"
+)
+
+var reThink = regexp.MustCompile(`(?is)<think>.*?</think>`)
+
+// RemoveThinkTags strips <think>...</think> blocks and trims whitespace.
+func RemoveThinkTags(s string) string {
+	return strings.TrimSpace(reThink.ReplaceAllString(s, ""))
+}
+
+// SanitizeAssistantMessages removes think tags from assistant messages while leaving others untouched.
+func SanitizeAssistantMessages(msgs []Message) []Message {
+	out := make([]Message, 0, len(msgs))
+	for _, m := range msgs {
+		if strings.EqualFold(strings.TrimSpace(m.Role), "assistant") {
+			out = append(out, Message{Role: m.Role, Text: RemoveThinkTags(m.Text)})
+			continue
+		}
+		out = append(out, m)
+	}
+	return out
+}
+
+// EqualMessages compares two message slices for equality.
+func EqualMessages(a, b []Message) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i].Role != b[i].Role || a[i].Text != b[i].Text {
+			return false
+		}
+	}
+	return true
+}